Mounting for the mast of a drilling rig for drilling either vertical or slanting holes



Apnl 12, 1966 H. 1.. BULES ETAL 3,245,180

MOUNTING FOR THE MAST OF A DRILLING RIG FOR DRILLING EITHER VERTICAL OR SLANTING HOLES Filed Dec. 6, 1962 5 Sheets$heet 1 INVENTOR5 flersc/we/ 1.. Bu/es, Byron M Snyder, James W. Weafhnsby, By aLmvCg/rce E. Pope.

A 77 0/?NE Y April 12, 1966 H. L. BULES ETAL 3,245,180

MOUNTING FOR THE MAST OF A DRILLING RIG FOR DRILLING EITHER VERTICAL OR SLANTING HOLES Aprll 12, 1966 H. L. BULES ETAL 3,245,180

MOUNTING FOR THE MAST OF A DRILLING RIG FOR DRILLING EITHER VERTICAL 0R SLANTING HOLES Filed Dec. 6, 1962 5 Sheets-Sheet 3 v INVENTORS flersc/le/ L. 50/65, Byron 5/zyaer James W Weafhers'ty,

By Maw/w 5. Papa.

A TTURNE) April 1966 H. L. BULES ETAL 3,245,180

MOUNTING FOR THE MAST OF A DRILLING RIG FOR DRILLING EITHER VERTICAL OR SLANTING HOLES 5 Sheets-Sheet 4.

Filed Dec. 6, 1962 x E INVENTORS 5* Q, flersche/ L. Bu/es,

Q I x 5 ran ll. 50 def R 1: James flweafhensbx g 5 By LaWre/me 5. Pope ATTORNEY April 1966 H. L.BULES ETAL 3,245,180

MOUNTING FOR THE MAST OF A DRILLING RIG FOR DRILLING EITHER VERTICAL OR SLANTING HOLES Filed Dec. 6, 1962 5 Sheets-Sheet 5 INVENTORS N. n fie/lsche/ L Bales E Q Byron 1 5/zyder James 14- Weafhersby "z, a v Law/e 06 5. Pa 5 BY fd 5 United States Patent MOUNTING FOR THE MAST OF A DRILLING RIG FOR DRILLING EITHER VERTICAL 0R SLANT- ING HOLES Herschel L. Bules, Byron V. Snyder, James W. Weathersby, and Lawrence E. Pope, Enid, 0kla., assignors to George E. Failing Company, Enid, Okla, a corporation of Delaware Filed Dec. 6, 1962, Ser. No. 242,662 13 Claims. (Cl. 52--116) This invention relates to drilling rigs of the type which include a mobile support carrying the drilling equipment and a mast that is pivotally mounted thereon to be moved from a reclining transport position to an erect position at the site of drilling operations. The mast, when in erected position, must have the base or lower end thereof located at a level convenient for work of the drilling crew. For this reason, the pivotal axis is usually provided by bearings supported at the top of stationary brackets that are of sufficient height for the mast to clear the drilling mechanisms, such as the power unit, draw works, pumps, compressors, et cetera, when the mast is in reclining or transport position. Such an arrangement brings the base of the mast in desired position for drilling vertical holes, but when slanting holes are to be drilled any angular adjustment of the mast raises the base of the mast and swings it away from the mobile support, consequently, the base of the mast is moved out of its desired position.

It is, therefore, a principal object of the present invention to provide an improved mounting for such masts, whereby the lower end or base of the mast is kept at substantially the same level whether drilling vertical or slanting holes.

In carrying out the invention, two pivotal axes are provided for the mast, a first pivotal axis on which the mast is raised from transport position to an erect position, and a second pivotal axis located near the base of the mast and on which the mast is pivoted, with the first pivotal axis moving in an arc about the second pivotal axis to bring the mast to slanting position.

Other objects of the invention are to provide the second pivotal axis by means of jack shafts that are movably carried by the mobile support and adapted to be projected into pivotal connection with the mast or to be retracted therefrom; to provide means for retaining the jack shafts locked in either retracted or projected position; to provide supports for the first pivotal axis that are adjustable about the second pivotal axis for supporting the mast in any one of its drilling positions; to provide hydraulic jacks for raising and lowering the mast and which cooperate with the adjustable supports and jack shafts for locking the mast in all its different drilling positions; and to provide mast supports which form rigid lateral braces for the mast in any of its pivotal positions.

In accomplishing these and other objects of the invention as hereinafter pointed out, we have provided improved structure, the preferred form of which is illustrated in the accompanying drawings, wherein:

FIG. 1 is a perspective view of a portion of a drilling rig for drilling either vertical or slanting holes, and showing the lower portion of the mast, the portion of the mobile support on which the mast is movably mounted, and the mechanisms for swinging the mast from a reclining transport position on the mobile support to an erect drilling position, together with the mechanism for positioning the mast to drill slanting holes.

FIG. 2 is a side elevational view of the parts shown in FIG. 1, with the mast in transport position on the mobile support, a part of the mobile support being broken away to illustrate the pivotal connections of the hydraulic jack and the brace legs.

3,245,18fi Patented Apr. 12, 1966 3 is a similar View, but showing the mast in erect position.

FIG. 4 is a similar view, but showing the mast in one angular position for drilling slanting holes and illustratmg the brace leg of the lefthand support in section.

FIG. 5 is a horizontal section on the line 55 of FIG. 3.

FIG. 6 is a perspective view of one of the pivotal supports for carrying the mast, showing its related bolt or jack shaft in spaced relation and on which the support is pivotally mounted when the parts are assembled in the rig.

FIG. 7 is a perspective view of the lower ends of one of the adjustable brace legs for the mast supports, the parts being disassembled and in spaced relation, to better show the construction thereof.

FIG. 8 is a section through one of the bolt shafts, taken on the line 8-8 of FIG. 9.

FIG. 9 is a section through the mast support and tilting assembly, the section being taken approximately on the line 99 of FIG. 2, and showing the mast in vertical position, with the bolt shafts engaged with the mast to provide the second pivotal axis.

FIG. 10 is an enlarged, fragmentary, horizontal section through one of the brackets that projects from the mast for carrying the shaft that connects the pivotal legs of the mast support with the brace leg.

FIG. 11 is an enlarged horizontal section through one of the brackets which connects one of the power cylinders with the mast.

FIG. 12 is a diagram of the ducts and valves supplying pressure medium to the raising and lowering jacks.

FIG. 13 is a side elevation of a modified form of the invention showing a part of the mobile support broken away to illustrate the pivotal connection of the hydraulic jack.

FIG. 14 is a similar View showing the position of the parts when the mast is in an inclined drilling position.

FIG. 15 is a detail section on the line 1515 of FIG. 13.

Referring more in detail to the drawings:

1 designates a drilling rig for drilling 'bore holes, and particularly bore holes that slant from the vertical. Since the rig 1 is of relatively large size, the drawings illustrate only that part of the rig that is involved in the present invention, in order that they may be made of as large a scale as possible, however, it is to be understood that the rig includes a mobile support 2 comprising a platform 3 mounted on skids, Wheels or crawlers 4. It is also to be understood that the platform carries the various mechanisms making up the drilling rig, such as a motive power unit, draw works, compressors, and other units to be used in drilling a bore hole, none of which are illustrated in the present drawings since they specifically form part of the present invention.

The platform 3 also mounts a mast 5 that is pivotally connected with the platform, to be carried in a reclining transport position, :as shown in FIG. 2. The mast is adapted to be raised from transport position to various drilling positions, as shown in FIGS. 1, 3, 4, 13 and 14. The mast illustrated includes rear legs 6 and 7 and front legs 8 and 9. The rear legs 6 and 7 are interconnected at points along the length thereof by girts 10 (FIGS. 1, 5 and 9) and sway braces 11, while the front legs 8 and 9 are connected with the corresponding rear legs 6 and 7 by girts 12 and sway braces .13, leaving an open front 14.

not shown in the drawings since they form no part of the present invention. The lower ends of the front legs 8 and 9 are connected at the sides with the rear legs 6 and 7 by plates 1515' which carry guide shoes 16-16 for positioning the mast, as later to be described.

While a specific construction of mast is illustrated in the drawings, it is to be understood that the mast may be of different construction and still be employed in the novel combination constituting the present invention.

In order that the mast, when in transport position (FIG. 2), may clear the various units carried on the platform, the pivotal axis 17 for the mast must be located at a substantial distance above the platform. This also necessitates mounting of the pivotal axis 17 at a substantial distance above the lower end of the mast, since the base of the mast must be kept at a convenient height when the mast is in erect position, as shown in FIGS. 1, 3 and 13, for drilling vertical holes.

It is obvious that with only the single pivotal axis 17, any rearward tilting of the mast on that axis, for drilling a slanting hole, results in raising the lower end of the mast and moving it away from the mobile support, so that it is out of the desired drilling position. Also, it is difficul-t to satisfactorily anchor the lower end of the mast to the platform. To avoid this difficulty, the present invention involves an additional pivotal axis 18 at the base or lower end of the mast, on which the mast is tilted, as shown in FIG. 4, when drilling slanting holes.

In providing the first pivotal axis 17, the sides of the mast are provided with laterally extending brackets 19 and 26, each including plates 21 and 22, spaced apart by arms 23 (FIGS. and The inner plate portion 22 of each bracket is welded or otherwise suitably attached to the outer faces of the legs 6 and 7 at a substantial distance from the lower end of the mast. Each of the brackets 19 and are rigidly connected to the front legs of the mast by braces 24 and 25. When the brackets are mounted, the plates 21 and 22 project rearwardly from the mast and carry pivot pins 26 and 27 (FIG. 9).

The second pivotal axis 18 includes tubular housings 28 (FIG. 8) that are carried by rear portions 30 and 31 of the platform which extend rearwardly at the sides of the base portion of the mast. The ends of the tubular housings 28 are carried in blocks 32 and 33 (FIG. 8) that are fixed to the substructure of the platform 3, as best shown in FIGS. 8 and 9. The tubular housings 28 are so mounted that they are fixed from turning relatively to the platform, for a purpose later described.

In order to provide the two pivotal axes 17 and 18, it is necessary to provide for rocking movement of the axis 17 on an are about the axis 18, as indicated by the dot and dash line designated 17' in FIGS. 3 and 4. In the illustrate-d instance, this is accomplished as now to be described.

Oscillatably mounted upon each tubular housing is a sleeve 3435, respectively (FIGS. 6, 8 and 9), which connects lower ends of legs 36 and 37 that are rigidly connected thereto. The legs 36 and 37 extend upwardly through openings 38 in the floor of the platform 3. The inner legs 36 are located in planes parallel with sides of the mast, however, the legs 37 are splayed from the legs 36 to form lateral braces. Fixed to the upper ends of the legs in registry with the pivotal axis 17 are heads 39 and 40 that are pivotally mounted on the pins 26 and 27, previously described. The legs 36 and 37 thus provide pivoted supports 41-42 on which the mast is carried to swing about the first :axis 17. The upper ends of the legs 36 and 37 are connected by cross members 43 (FIGS. 1, 6 and 9) to space the heads 39 and 40 on the pins 26 and 27, to accommodate therebetween heads 44 on the upper ends of brace legs 45 and 46. The brace legs extend downwardly and forwardly through an opening 47 in the platform, for pivotal connection with pins 48 and 49 (FIGS. 2, 3, 4 and 5). The pins 48 and 49 are carried by brackets 50 and 51, mounted on a 4 transverse structural member 52 of the platform, as shown in FIGS. 2, 3, 4 and 5. The brace legs control pivotal movement of the mast supports, and hold the mast supports in fixed position when the mast is pivoting on the axis 17.

In the illustration, the brace legs 45 and 46 are telescopically adjustable as to length, in that they comprise one member 53 which carries a head 44, and a tubular member 54 in which the member 53 is slidable, as best shown in FIG. 4. Fixed to the lower end of each tubular member 54 is a transverse sleeve 55, pivotally oscillatable on the pins 48 and 49.

In order to adjust the brace legs for maintaining the support legs 41 and 42 in a fixed position, the tubular members 54 are provided in the wall thereof with a series of spaced apart apertures 57 extending diametrically therethrough. The lower ends of the inner members 53 are provided with notches 58 (FIG. 7) that are selectively registrable with the apertures 57. A stop pin 59 is inserted through a selected one of the apertures 57 of each cylindrical member, to be engaged by the notched ends of the members 53. Each stop pin is provided with a collar 60, carrying a suitable head 61 by which the stop pins may be easily withdrawn from one aperture 57 and placed in other of the apertures.

The mast is raised and lowered by jack means 62 and 63, each including a cylinder 64 having a transverse sleeve 65 fixed to the lower end thereof. Slidable in the respective cylinders are pistons 66 (FIG. 12) which are attached to piston rods 68 movable through seals 69 closing the upper ends of the cylinders. The upper ends of the piston rods have heads 70 pivotally connected with a shaft 71 extending transversely of the rear legs of the mast at a point above the pivotal axis 17. The sleeves 65 are pivotally mounted on pins 72 having ends thereof carried in spaced bearing brackets 73 and 74 (FIG. 5) that are mounted on a transverse sill 75 forming a part of the framing structure of the platform. The transverse shaft 71 has the ends thereof carried in plates 76 and 77 that are welded to the inner faces of the rear legs 6 and 7 of the mast, as best shown in FIGS. 5 and 11.

In order to pivot the mast on the axis 18 for movement to any one of its slanting positions, each sleeve 34 and 35 mounts therein a jack shaft 78 and 79, respectively, that are adapted to be reciprocated into and out of connection with the lower end of the mast. In the illustrated instance each jack shaft 78 and 79 has threaded portions 80 for engaging internal threads 81 (FIG. 8) that are formed in counterbores 82 of the sleeves 28. Projecting from the inner end of each jack shaft is a trunnion 83 which engages in apertures 84 that are provided in plates 15-15 and the guide shoes 1616 at the base of the mast 5, previously described, to pivotally carry the mast on the pivotal axis 18. The jack shafts 78 and 75 are rotated within the sleeves 28 from the respective sides of the platform 3 by providing jack shafts of sufficient length to project from the outer sides of the platform and which projecting ends are provided with slots 86, or otherwise formed to be engaged by a suitable rotating tool, not shown.

It is to be understood that the invention is not to be restricted to the above described means for reciprocating the jack shafts, as it is obvious that other means may be provided for moving the trunnions into and out of the apertures 84.

A Pressure medium, such as a liquid under high pres sure, is supplied to the respective ends of the cylinders 64 through ducts 87 and 88 which are indicated in diagram in FIG. 12. The ducts 87 of each cylinder are connected with a common duct 89 leading to a four-way valve 96. The ducts 88 from each cylinder are also connected with a common duct 91, also leading to the valve 20. The valve 90 is supplied with the pressure fluid through a duct 92, and the pressure fluid is exhausted from the valve through a return duct 93.

The guide shoes 1646' have ends 94 and 95 projecting from the legs 6 and 7 of the mast to guide the lower end of the mast between the portions 31 of the platform when the mast is to be moved to position for connecting the trunnion portions of the jack shafts 78 and 79 with the mast.

When the mast 5 is in transport position, shown in FIG. 2, the stop pins 59 of the brace legs 41 and 42 are in the apertures 57 of the tubular members 54 most remote from the pivot pins 48 and 49, and the notches 58 in the ends of the inner members 53 are seating upon the stop pins 59. The hydraulic jacks 62 and 63 are retracted so that they cooperate with the supports 41 and 42 to hold the mast stationary in transport position. A rest (not shown) is provided at the front end of the mobile support to carry the top of the mast 5, as is the usual practice. The rest is not shown because it is well known and forms no part of the present invention.

When the mast is to be raised, care is taken to see that the trunnions 83 of the jack shafts 78 and 79 are fully retractedwithin the housings 28. If they are not, the jack shafts 78 and 79 are retracted by placing a bar or the like in the slots 86, and rotating them to unscrew the threads 81 until the trunnions 83 are retracted.

To raise the mast toward a vertical drilling position, the valve 90 is opened so that hydraulic fluid under pressure in the duct 92 is delivered to the lower ends of the cylinders 64 of the hydraulic jacks 62 and 63 by way of the duct 91 and branch ducts 88, to act upon the lower ends of the pistons 66. The valve 90, in this position, opens an exhaust flow of fluid from above the pistons 66 by way of the branch ducts 87, duct 91, to the exhaust line 93. The pistons now move under hydraulic pressure toward the upper ends of the cylinders 64. This movement of the pistons imparts thrust upon the piston rods 68 and causes the mast to swing about the first pivotal axis 17, with the upper end swinging upwardly and the lower end moving downwardly and entering the space between the platform portions 30 and 31. When the mast 5 is in upright position, the apertures 84 at the lower end of the mast will register with the trunnion portions 83 of the jack shafts 78 and 79. The valve 90 is now turned to shut otf the supply and exhaust of pressure fluid to and from the hydraulic cylinders 64, to trap fluid on the respective sides of the pistons 66 and thereby prevent further movement of the mast in either direction. During this movement of the mast 5, the hydraulic jacks 62 and 63 pivot upon the pins 65 and the transverse shaft 71, but there is no movement of the mast supports 41 and 42. The jack shafts 78 and 79 are then rotated in a direction to project the trunnions 83 into the apertures 84. Projection of the trunnions 83 is brought about by the threads 80 on the jack shafts 73 and 79 turning within the internal threads 81 of the fixed sleeves 28 that are rigidly carried by the mobile support. The mast is now locked in vertical position, and the drilling rig may be used for drilling vertical holes.

To slant the mast 5, as shown in FIG. 4, for drilling slanting holes, the valve 90 is adjusted to admit hydraulic fluid to one or the other ends of the cylinders 64, for relieving pressure on the stop pins 59. The stop plus 59 are now easily withdrawn from the uppermost apertures 57. The pins 59 are then inserted in one of the apertures 57 to give a desired slant to the mast; for example, the stop pins 59 may be inserted into the apertures 57 closest to the pivot pins 48 and 49. This leaves the members 53 free to telescope into the tubular members 54, but movement of the mast is under control of the hydraulic jacks 6'2 and 63. The Valve 90 is then adjusted so that the pressure fluid is delivered from the duct 92 through the duct 89 and branch ducts 87 to the upper ends of the cylinders 64, and the duct 91 is connected to the duct 93 so that pressure fluid acts above the pistons 66 and exhausts below the pistons. The mast now begins a reverse movement, but this time the mast swings upon the trunnions 8 3 about the second pivotal axis 18 responsive to pull of the piston rods 68 on the transverse shaft 71. During this movement of the mast, the legs 36 and 37 of the supports swing upon the sleeves 28 and since the pins 26 and 27 permanently connect the mast with the supports 41 and 42, they cause the members 53 to slide into the tubular members 54 until the notched ends of the members 53 come into seating contact with the pins 59, to stop the mast in slanting position (FIG. 4), whereupon the valve is readjusted to shut ofl the supply of pressure fluid and to hold pressure on the cylinders 64 on both sides of the pistons 66. During telescoping of the members 53 into the tubular members 54 of the brace legs, the brace legs pivot upon the pins 26-27 and 4849 and remain connected, with the brackets 19 and 20 to cooperate with the jack sha-fts 78 in holding the mast in its slanting position.

It is obvious that when the mast 5 is pivoted upon the fixed pivotal axis 18, the entire mast moves in the same direction relatively to the axis 18, consequently, there is no lifting of the lower end of the mast or movement of the lower end of the mast away from the mobile support 2, as would be the case if the mast entirely pivoted on the pivotal axis 17. It is also obvious that the lower end of the mast is firmly locked to the mobile support by the trunnions 83 of the jack shafts 78 and 79.

To lower the mast to transport position, the valve 90 is first adjusted to admit hydraulic fluid to the lower ends of the cylinders 64, for acting on the lower ends of the pistons and pushing the piston rods 68 outwardly from the cylinders 64 to raise the most to perpendicular position. During this movement, the members 53 of the brace legs slide outwardly in the tubular members 54 away from the stop pins 59, since the brackets 19 and 20 are carried forwardly with the mast. The pins 59 are then easily withdrawn and reinserted in the uppermost apertures 57, to hold the pivotal axis 17 at transport level. The jack shafts 78 and 79 are then retracted to withdraw the trunnions 83 from the apertures 84 to free the lower end of the mast. The mast is now free to swing to transport position upon adjusting the valve 90 to admit fluid to the upper ends of the cylinders 64 and exhaust the fluid from the lower ends of the cylinders.

It is important that when the mast is tilted to an inclined drilling position, the first pivotal axis 17 shifts in an are about the axis 18, as indicated by the arcuate lines 17', FIGS. 3 and 4, under movement by the hydraulic jacks 62 and 63.

Another one of the desirable means for attaining this etfect is illustrated in FIGS. l3, l4 and 15, in which the supports may comprise rigid posts 96 and braces 97, fixed to the platform 3, to carry upon the upper ends thereof arcuate guides 98, having rails 99 curving about the axis of the jack shafts 78 and 79 which constitutes the second pivotal axis 18. The rails 99 slidably mount thereon brackets 100 which journal trunnions 101 projecting from the sides of the mast 5. The rails have laterally extending flanges 102. The brackets have shoe portions 103 slidable on the rails. The shoe portions have inturned flanges 104 and 105 (FIG. 15) engaging under the flanges 102 of the rails 99 to slidably anchor the shoes 103. In this structure, the mast is held in its drilling positions by the jack shafts 78 and 79 and the hydraulic jacks 62 and 63, and/or locks incorporated within the shoe portions 103.

In raising the mast from horizontal position, the mast swings on the trunnions 101 to an upright position, as shown in FIG. 13. After the trunnions on the jack shafts 78 and 79 are connected with the lower portion of the mast, the mast pivots to an inclined drilling position (FIG. 14) only on the trunnion portions of the jack shafts, and the brackets 100 slide upon the arcuate rails 99. The construction and operation of the modified form are the same as in the first described form of the invention.

What is claimed and desired to be secured by letters Patent is:

1. In a drilling rig for drilling slanting holes,

a support,

a mast having a lower end to be maintained near a constant height and position relatively to the support when the mast is in drilling positions,

a first pivot means carried by the support and having a permanent connection with a portion of the mast above said lower end to provide a first pivotal axis on which the mast bodily swings from a reclining position spaced above the support to an erect position with said lower end of the mast swinging downwardly to said support,

a second pivot means carried on the support below the level of the first pivot means for pivotal connection with said lower end of the mast to provide a second pivotal axis on which the mast is pivoted from said erect position to a slanted position, and

means for adjusting the extent of movement of the first pivotal axis about the second pivotal axis while both said first and second pivot means remain in connection with the mast when the mast swings on said second pivotal axis to the slanted position.

2. In a drilling rig for drilling slanting holes as described in claim ll,

means on the support and connected with the mast for swinging the mast on said first pivotal axis to erect position and subsequently swinging the mast on said second pivotal axis to said slanted position.

3. In a drilling rig for drilling slanting holes,

a support,

a mast having a lower end to be maintained near a.

constant height and position relatively to the support when the mast is in various drilling positions,

a first means having pivotal connection with the mast at a point above said lower end to provide a first pivotal axis on which the mast is pivoted from a substantially horizontal carrying position to .a substantially vertical position,

a jack means having pivotal connection with the support and with the mast above the connection of the first pivotal means for swinging the mast upwardly about said first pivotal axis and swinging the lower end of the mast downwardly from carrying position toward the support,

a second pivotal means on the support for pivotal connection with the lower end of the mast to provide a second pivotal axis on which the mast is pivoted to a slanting position,

and means for movably earring the first means on the support to shift the first pivotal axis arcuately about the second pivotal axis during pivoting of the mast on said second pivotal axis when the mast is moved to drill a slanting hole.

4. In a drilling rig for drilling slanting holes as described in claim 3,

wherein the means for movably carrying the first means is fixed to the support and has arcuate rails at the upper end,

and said first means has portions slidably movable on the rails.

5. In a drilling rig for drilling slanting holes,

a support,

a mast having a lower end to be maintained near a constant height and position relatively to the support when the mast is in various slanting positions,

mast supporting means having connection with the support at opposite sides of the mast and having pivotal connection with the mast at a point above said lower end of the mast,

means for swinging the mast about said pivotal axis for swinging the upper end of the mast upwardly and said lower end of the mast downwardly when the mast is moved from reclining position toward erect position, and

pivotal means movable on the support into connection with the lower end of the mast for providing a second pivotal axis on which the mast is pivoted to a slanting position upon reversal of the mast swinging means.

6. In a drilling rig for drilling slanting holes,

a support,

a mast having a lower end to be maintained near a constant height and position relatively to the support when the mast is in various drilling positions,

mast supporting means on the support at opposite sides of the mast and having pivotal connect-ion with the support and pivotal connection with the mast at a point above said lower end of the mast,

adjustable means on the support having connection with the mast supporting means and holding the pivotal connection with the mast in fixed position on the support to carry the mast in reclining position above the support and to provide a first pivotal axis on which the mast is adapted to swing toward a substantially erect position,

means for swinging the mast about said pivotal axis for bringing said lower end downwardly to said sup port when moving the mast from reclining position toward erect position, and

pivotal means movable on the support into connection with the lower end of the mast to provide a second pivotal axis on which the mast is pivoted to a slanting position after adjustment of said adjustable means and upon reversal of the mast swinging means.

7. In a drilling rig for drilling slanting holes,

a support,

a mast having a lower end to be maintained near a constant height and position relatively to the support when the mast is in various drilling positions,

mast supports spaced apart on the support and having pivotal connection with the support at opposite sides of the mast and having pivotal connection with the mast at a point above said lower end of the mast whereby the lower end of the mast swings downwardly between the mast support to come into said constant height position when the mast is moved from a reclining position on the support to drilling position,

adjustable means on the support and having connection with the mast supporting means to hold the pivotal connection with the mast in fixed position on the support when the mast swings from said reclining position above the support toward a substantially erect position,

pivotal means coaxial with the connection of the mast supporting means with said support to provide a second pivotal axis on which the mast is pivoted to a slanting position after adjustment of said adjustable means, and

means on the support for swinging the mast on said first pivotal axis and subsequently swinging the mast on said second pivotal axis.

8. In a drilling rig for drilling slanting holes,

a mobile support,

a mast having a lower end to be maintained near a constant height and position relatively to the mobile support when the mast is in various drilling positions,

mast supporting means on the mobile support at opposite sides of the mast and having pivotal connection with the mobile support and pivotal connection with the mast at a point above said lower end of the mast,

adjustable means on the mobile support and having connection with the mast supporting means to hold the pivotal connection with the mast in fixed position on the mobile support to carry the mast in reclining position above the mobile support and to provide a first pivotal axis on which the mast is adapted to swing toward a substantially erect position,

means for swinging the mast about said pivotal axis for moving the mast from reclining position toward erect position, and

jack shafts rotatable on the mobile support at opposite sides of the mast and having screw threaded connection with the mobile support for effecting axial movement of the jack shafts into connection with the lower end of the mast to provide a second pivotal axis on which the mast is pivoted to a slanting position after adjustment of said adjustable means and upon reversal of the mast swinging means.

9. In a drilling rig for drilling slanting holes,

a mobile support,

a mast having a lower end to be maintained near a constant height and position relatively to the mobile support when the mast is in various drilling positions,

mast supporting means on the mobile support at opposite sides of the mast and having pivotal connection with the mobile support and pivotal connection with the mast at a point above said lower end of the mast,

brace means on the mobile support and having connection with the mast supporting means to hold the pivotal connection with the mast in fixed position on the mobile support to carry the mast in reclining position above the mobile support and to provide a first pivotal axis on which the mast is adapted to swing toward a substatnially erect position,

said brace means comprising telescoping members slidable relatively to each other,

stop means adjustably carried by one of the members and adapted to be engaged by the other member for holding said mast supporting means in fixed position and removable to permit telescoping of said members,

means for swinging the mast about said pivotal axis for moving the mast from reclining position toward erect position, and

jack shafts rotatable on the mobile support at opposite sides of the mast and having screw threaded connection for effecting axial movement of said jack shafts into connection with the lower end of the mast to provide a second pivotal axis on which the mast is pivoted by said mast moving means to a slanting position after removal and replacement of said stop means to hold the slant of the mast.

10. In a drilling rig for drilling slanting holes,

a mobile support,

a mast having a lower end to be maintained near a constant height and position relatively to the mobile support when the mast is in various drilling positions,

mast supporting means on the mobile support at opposite sides of the mast and having pivotal connection with the mobile support and pivotal connection with the mast at a point above said lower end of the mast,

brace means on the mobile support and having connection with the mast supporting means to hold the pivotal connection with the mast in fixed position on the mobile support to carry the mast in reclining position above the mobile support and to provide a first pivotal axis on which the mast is adapted to swing toward a substantially erect position,

said brace means comprising telescoping members slidable relatively to each other,

stop means adjustably carried by one of the members and adapted to be engaged by the other member for holding said mast supporting means in fixed position and removable to permit telescoping of said members,

means for swinging the mast about said pivotal axis for moving the mast from reclining position toward erect position, and

pivotal means movable on the mobile support into connection with the lower end of the mast to provide a second pivotal axis on which the mast is pivoted by said mast moving means to a slanting position after removal and replacement of said stop means to hold the slant of the mast.

11. In a drilling rig for drilling slanting holes,

, a mobile support,

a mast having a lower end to be maintained near a constant height and position relatively to the mobile support when the mast is in various drilling positions,

said lower end of the mast having apertures on opposite sides,

supports at opposite sides of the mast each having splayed apart rigid legs and an adjustable brace leg,

brackets projecting from sides of the mast above the lower end thereof,

pins passing through upper ends of the legs and carried in said brackets to provide a first pivotal axis for the mast,

sleeves connecting lower ends of the rigid legs,

fixed sleeves extending through the first sleeves on which the rigid legs are pivotally connected to the mobile support, and

jack shafts reciprocable within the fixed sleeves to project into said apertures for providing a second pivotal axis for the mast.

12. In a drilling rig for drilling slanting holes,

a mobile support,

a mast having a lower end to be maintained near a constant height and position relatively to the mobile support when the mast is in various drilling positions,

said lower end of the mast having apertures on opposite sides,

supports at opposite sides of the mast each having splayed rigid legs and an adjustable brace leg,

brackets projecting from sides of the mast above the lower end thereof,

shafts passing through upper ends of said legs and carried by said brackets to provide a pivotal axis for the mast,

sleeves interconnecting the lower ends of the splayed legs,

fixed sleeves extending through the first sleeves on which the rigid legs are pivotally connected to the mobile support,

jack shafts movable within the fixed sleeves to project ends thereof into said apertures for providing a second pivotal axis for the mast, and

jack means connecting the mast with the mobile support for swinging the mast on said first pivotal axis to register the recesses with the jack shafts and to swing said mast upon said second pivotal axis when the jack shafts are projected into the recesses and after removal and readjustment of said stops for slanting the mast.

13. In a drilling rig for drilling slanting holes,

a mobile support,

a mast having a lower end to be maintained near a constant height and position relatively to the mobile support when the mast is in various drilling positions,

said lower end of the mast having apertures on opposite sides,

supports at opposite sides of the mast each having splayed legs and an adjustable brace leg,

brackets projecting from sides of the mast above the lower end thereof,

shafts passing through upper ends of the legs and carried in said brackets to provide a first pivotal axis for the mast,

sleeves interconnecting the lower ends of the splayed legs,

fixed sleeves extending through the first sleeves and on which the s'played legs are pivotally connected to the mobile support,

jack shafts rotatable within the fixed sleeves and having threaded connection therewith to project ends of the jack shafts into said apertures on opposite sides of the mast for providing a second pivotal axis for the mast,

said brace legs comprising telescoping tubular members,

the outer of said tubular members having a series of spaced apart apertures and the inner tubular members having seats in ends thereof,

means for pivotally connecting lower ends of the brace legs to the mobile support,

of the adjustable legs of each support to be engaged by the seats of the inner members, and

jack means connecting the mast with the mobile support for swinging the mast on said first pivotal axis to register the recesses with the jack shafts and to control swinging of the mast upon said second pivotal axis when the jack shafts are projected into the recesses and after removal and readjustment of said stops for slanting the mast to a position set by the stop pins.

References Cited by the Examiner UNITED STATES PATENTS 2,711,803 6/1955 Hurst 52115 2,790,622 4/1957 Priest 52-119 X 3,109,523 11/1963 Moller 52115 FRANK L. ABBOTT, Primary Examiner.

stop pins for insertion through one of said openings 20 RICHARD W. COOKE, In, Examiner. 

1. IN A DRILLING RIG FOR DRILLING SLANTING HOLES, A SUPPORT, A MAST HAVING A LOWER END TO BE MAINTAINED NEAR A CONSTANT HEIGHT AND POSITION RELATIVELY TO THE SUPPORT WHEN THE MAST IS IN DRILLING POSITIONS, A FIRST PIVOT MEANS CARRIED BY THE SUPPORT AND HAVING A PERMANENT CONNECTION WITH A PORTION OF THE MAST ABOVE SAID LOWER END TO PROVIDE A FIRST PIVOTAL AXIS ON WHICH THE MAST BODILY SWINGS FROM A RECLINING POSITION SPACED ABOVE THE SUPPORT TO AN ERECT POSITION WITH SAID LOWER END OF THE MAST SWINGING DOWNWARDLY TO SAID SUPPORT, A SECOND PIVOT MEANS CARRIED ON THE SUPPORT BELOW THE LEVEL OF THE FIRST PIVOT MEANS FOR PIVOTAL CONNECTION WITH SAID LOWER END OF THE MAST TO PROVIDE A SECOND PIVOTAL AXIS ON WHICH THE MAST IS PIVOTED FROM SAID ERECT POSITION TO A SLANTED POSITION, AND MEANS FOR ADJUSTING THE EXTENT OF MOVEMENT OF THE FIRST PIVOTAL AXIS ABOUT THE SECOND PIVOTAL AXIS WHILE BOTH SAID FIRST AND SECOND PIVOT MEANS REMAIN IN CONNECTION WITH THE MAST WHEN THE MAST SWINGS ON SAID SECOND PIVOTAL AXIS TO THE SLANTED POSITION. 